534 



THE SMALL GRAINS 



The mycelium consists of short septate hyphae, dark brown in 

 color, later forming acervuli varying from about 30 /u, to 1 mm. in 

 diameter. Upon these are developed the conidiospores, which 



in turn produce the ellip- 

 soidal, hyaline, guttulate 

 sj>ores. 



v \ Witt/.- This fungus is par- 



ticularly injurious to 

 rye. Its presence is 

 shown by the perma- 

 nent dying of those 

 portions of the spikes 

 above the point of 

 attack, resulting in al- 

 most total loss of grain 

 in these dead portions. 

 It also attacks the 

 roots and basal portions 

 of the rye culms, pro- 

 ducing a blackened 

 appearance of the af- 

 fected parts. On wheat 

 there is no special at- 

 tack of the spike and 

 less root attack, but 

 there is a premature 

 whitening and ripen- 



FIG. 167. Ergot on rye: a, spike with 

 ergot in place of some kernels ; b : ergot- 

 ized kernels ; above 6, sound kernels. 



ing of the plant. 

 The spores of this fungus are easily disseminated through 

 seed grain. These will be readily destroyed by the for- 

 malin seed treatment. There are no doubt other sources 

 of infection, however, because of the occurrence of the 

 fungus on straw and on the culms of grasses. 



